Circuit controller



May 13, 1924. 1,494,320 O. P. CRAMER CIRCUIT CONTROLLER Filed July 11. 1922 2 Sheets-sheet 1 ATTORNEYS.

May 13, 1924. 1,494,320

` O. P. CRAMER CIRCUIT ,CONTROLLER f'lG. 6.

' ATTORNEYS.

iti

Patented May 13,l 1924.

gorro?. emmer. sAN MATEO, CALIFORNIA.

A cmcurr CONTROLLER.

Y Anuman lied July 11, 1922. serial 1ro. 574,254.

To concewi: Il

Be it known that I, O'i'ro P. CRAMER, a

citizen of the German Republic, and a resi dent ofthe cit'y of'San Mateo, in the county of San'Mateo and State 'of California, have invented a new and useful"Circuit' Controller, of which the following isa specifi cation.

' This invention relates to a circuit inter'- rupting device, and more articularly to a thermal responsive circuit reaker. Such a device finds great utility in ordinary dwellings where it is essentialA to maintain the load at a safe value to prevent fires. vFor such purposes it has been. common to use fusible metallic conductors, usually ltermed 4 fuses, that melt and interrupt the circuit when the load becomes suiciently great. The use of such fuses is attended with many disadvantages. The blowing of a fuse re- `quires replacement. stances the consumer finds fit impraoticable to renew the fuse himself, or else he feels that the safest course is to obtain the services 'of an electrician. there is a delay as well as an expense involved. Furthermore, fuses' in general are not the best form of safeguard, since there is no certaintyT that they will blowat any predetermined amperage; in fact they are .designated universally by their'safe carry` ing capacity, and by 'how much .it is possible to overload a fuse no one is capable of foretelling. This condition arises from the inherently variable factors entering into the manufacture Vof the fuses and also into the conditions ofoperation. A small variation,

'for example in physical dimensions, or in chemical composition, may cause a 'large variation in the amount of currentnecessary to blow the fuse. For this reason.l there is thus little assurance that a fusewill protect a dwelling from fire.. Still another disadvantage. resides in the use of unauthorized -heavy copper jumpers to replace the fusible wire; this is quite often resortedto by careless or ignorant persons who desire to rid themselves" of the annoyance of frequent' fuse renewals. Y

It-would of course be ossible to overcome all these disadvantages y installing a -circuit breaker. -In substantially all cases, however, such an'instaliation is prohibitive from the standpoint of cost. Itis thus one of the objects of my invention to provide an extremely inexpensive circuit controller In a great many in- In either case4 made serve the same purpose as an ordinary circuit breaker.

A other object of vide a circuit. controller extremely Simp e to close it,there would be no necessity for delaying .it until a skilled person arrives.

Another object vof.. my invention is to reduce as far as possible thevr manufacture oost of such a controller, so that it may compare favorably as regards first cost and maintenance expense with the ordinary fuse which must be replaced lafter each loperation.

Another object of my invention is to provide an inexpensive thermally o erated circuit controller, in which the e ect of the temperature of the surroundiiigair is coinpensated, whereby it is possible to set the apparatus accurately to cause it to open the circuitl upon apredetermined current load.

My invention possesses other advantageous features, some of which, with the foregoing, will be set forth at length in the following description where I shall outline in full that form of the invention which I have selected .for illustration in the drawings accompanying and forming part of the present specification. In the drawings I have shown but one embodiment of my invention, but it is to be understood that I do not. desire to vbe limited thereto, silice the invention as vexpressed in the claims may be embodied inother forms as well.

Referring to the drawings:

my invention is to ro` operate, so that in case it is desired to ref Figure 1' is a top plan view of a simple. embodiment of my invention,l with the cover mey parts of 4the device.v Upon this base are mounted the main switch contacts, comprising the stationary spring clipsflQ, 12" and 18, and the cooperating movable biades 14 and l5.` These form in effect a double pole switch.' In order to provide for appropsiate connections for one lof the incoming lines,

f a conducting strip' 16, is fastened to the stationary clips 12 and 12' and extendsalong a base 17 of. insulating material. vThis stripI 16 is 'fastenedV inv any appropriate manner to base 17, and carrlesa convenient binding post orterminal 18 -to which the in- 4 coming lead 19may be connected. To the' Aother pair of stationary clips 13 is attached in .any appropriate manner the conducting strip 2O carrying the other terimnal 21 tov which the other incoming line 221s con,

nected. Ther strips 16 and 20- also serve in a measure to support the base or panel 11 above the base 17,and they are shown in section in-Fig. 3, in close proximity to the edge of base 11. v The blade 14, adapted to enter between the clips 12 and 12 is pivoted in a pair ofspring supports 23, and is urged to open .pos1tion by any .a propriate device such as the sprin 24, coiled about the pivot pin' face when the contact is broken. .This bev# v32, the lower arm 36 'of lip, 25 on the clip, 12, which lip extends beyond the lower v,clip 12'... In this way when the blade mvoves'away from the clip 12, the

,sparking extendsl only between the beveled surface 24 and thelip 25; no pitting'or other bad eects destroythe smoothness of the main'contactsurfaces. c The life` of the contacts by the provision of this expedient is indefinitely prolonged. p

The 'blade' 15 is urgedalso toward open position byv an appropriate device, such as sprin 26, acting against in 37 on blade 15, w ich spring is coil about the in 27 acting as a pivot for the blade 15. 's blade is pivoted between spring clips 28, and is provided with av beveled surface 29 similar to that on blade 14, forcoacting with the upturned lip 30 of cli 13.

handle 31, fastened to the b ade 15 and preferably insulated therefrom may be used for vrnanually-closingr both contacts. To accomplish this result. handle 31l is first rofated in a counter-clockwise 'direction from the position shown in Fig. 2; this causes the upper edge of blade 15 to Contact with the 1 free end et" blade 14, and to push' this blade between clips 12, on continued rotation of handle 31. An appropriate latch 'to/.be her'e vinafter described retains blade' 1e in closed position again-st the pressure of spring Miter the blade 1&1 is latched, the handle 31 is rotated ina clockwise direction until blade 15 enters between clips 13. This blade is adapted to be latched bye, pivoted lever which is adapted to engage the sheen@ 'iii'.e lar-fle. 15. lever 32 is urged normally te engaging l position respectively in Figs. 1 and 2.

position by the spring A34. However, the upper arm 35 is in the ath of movement of a projection 'or pin 36 on lade 14, so that while this lblade -14 is open, the'lower arm 36 is moved out so that it cannot engage with the.

the 'y are opened and closed in succession,

an not simultaneously, has a great advantage when it is attempted to close the contacts before the' load is 'reduced to |a safel value.- Assume that there is a shortcircuit across the terminals -of clips 23 and 28,or that translating devices, too many -for the handle 31 is rotated in a counterclocksafety, are connected across these clips.

tween` 'clips 12,-but as, soon as the clockwise vrotation of the handle causes blade 15 -to contact with cli s 13, the latch holding blade 14 is tripped ue to the unsafe condition of the circuit. The opening of blade14` of .course prevents the arm .36 from engaging shoulder33 of blade 15, so thatit springs' open also. -It is thus seen that the circuit can be completed only for an extremely shortk interval of time.- vThis is due inv ameasure to the fact that the circuit iscomausl pleted'only when nthe blade I15 is closed. At

-that time this blade has moved far enough away from blade 14 so that this latter blade v is not prevented from opening, and is thus responsive' even before completion of the circuit to thereleasing of the latch holding'it.

In this respect my device diers'materially from an ordinary circuit breaker-,which is so .arranged that the movement of the contactsl to closed position prevents their immediate response tothe tripping of the Y latch. e

The latch which holds blade 14 in closed position and which acts in response to an unsafe load is re resented in closed and o en oted at 381s an arm 39 which isi-urged in a clockwise direction by a coiled spring 10. Pivoted also at 38 is a shorterlatch arm el whichhas a projection 42 coa'ctin. with .the end ci blade 14. Thepivot 25 o iv-M.

11:57l baat it,

and pivot 38 ef arm 41 areso'disposed rela- 4 tively to each other that the pressure of blade 14 against projection 42 is substantially in line with the pivot 38. ln this way spring 24 merely causes a compressive stress to he applied upon the arm lli, and theblade le ispreventea from opening. The arm el.

has a. member 43 extending below arm 32, and a. spring 4e is so arranged that` there 1s a tendency to rotate arm 41 in a counter clockwise directionwith respectv to arm 39, but'is prevented from doing by the .engages side' er" arm 39. The, epring ro- 'je-ction e5 on member 43, which proie nection between arms 39 and 41 is necea-ry in order that duringthe closi of blade 14, projection 42 may ride over the edge of .this blade without the necessity of moving arm 39.

The friction' between the projection 42 and theblade 14 is more than overcome by the spring 40,k which if it were allowed to act, would cause rotation of arm 39 to the position of Fig.4 2,"and the blade 14 would be released. It is however, prevented during normal conditions on the circuit, by the engagement of aiprojecton 46 on arm 39- with a projection '47 ,carried on an arm 48 pivoted at 49 to alever 50, which is in turn pivoted at 51 by means of a screw 52 .threaded through lever 50,. as. clearly shown in Fig. 5. A spring 53 is soarranged thatit urges arm 4 8 in a counterclockwise direction-with respect to.y lever 50, but is prevented from doing sc .bythe projection 54. The provision of the scre\`v.5 2lin lace of v a cimventionall pivot pin hasV the a vantage that the lever 50 does not bear against any. `fiat shoulder; `'instead' ,its tappedgapferture rests'upon the' helical surface of screw,` 52,

v and there is much less friction ,tham with the ordinary arrangement. It is of prime importance to reduce Athisfrictolvl. since it vico.l

.is this lever which ismo'ved directly by?" the thermally responsiveelement ofmyde- -base 11. A- thermally responsive element consisting of va pair of finewires 58 and 59' of conducting mfaterial is provided. These wires are preferably copper although other suitable material may be used.' They are so arranged in the electric circuit that a delinite'- portion ofthe current passes through them and causes them to heat. If the temperature is suiciently great, they eapand and permit spring 55 to withdraw the p rojec'tion 47 from below projection 46 on arm 39. The use of a plurality of looped wires to effect this result is described and claimed in a co-pendingapplcation in my name, en-

titled Electric safetv devices with time ad-y justment. having Serial No. 492.438. and filed August 15. 1921. v

To perform the desired functions, one end of wire 58 is connected to an eye 60 made of insulating material and looped over the arm 56 of lever 50. The other end of wire 58 lis fastened as b v screw 61 to a lever 62 pivoted to a brass strip 66 at 63. This lever is made of insulating material such as fibre. The wire 59 is'connected to a statiqnary post operation 64'at one end, and at the other end to the .influence of the current so as to reduce the tenslon by a predetermined amount, thev lever 50 is rotated by the spring 55-to performthe latch vtripping function. The expensions of wires 58 and 59 are added up by the aid of `lever 50, and in this regard this disclosure is somewhat similar'to that of my prior application heretofore identified.v In the present instance the wires 58 and 59 are' located in opposite sides of the circuit although such an arrangement is by no means essential. f 1

The mounting ofthe lever '62 on the brass bar 66 affords a convenient means for compensating for the temperature ofthe circumambient atmosphere. The bar has a projection 67 abutting against an adjustable screw 68. and is free to slide on expand longitudinally due "to the provision of slots 69 in the bar. The screw 68 affords anextremely convenientmeans for manually adjusting the tension of the wires 58 and 59. When the temperature of the atmosphere is high there is a tendency for the tension o wires 58 and 59 -to decrease, but in the present arrangement. this is overcome by the expension of bar 66 which automatically takes come bythe contraction of bar 66. In this way it is possible to set the point at which the switch releases with great accuracy,`by properly determining the initial or no load tension.

Thev mechanism whereby the latch is restored when the blades are closed is made directly responsive to the movement of handle 31. This mechanism com rises a control plate 70 shown in dot-dash ines in Fig. 1 and overlying many of the operating parts. This plate is preferably made offinsulating material or is otherwise insulated from the live parts of the mechanism. It is plvoted to the base 11 by means of the pivot 7'1, and

fjoa

. up the slack. When. the temperature is -lo'w the tendency to increase the tension is overlll is provided at'its free endwith a slot 72'r in which is engaged the'pin 37 fixed to blade 15. This slot and pin connection serves as a convenient means for rotating the control 'plate 70 in responseto the mo'vement of handle 31. -Thus when the handle is`v first moved in a counter-clockwise direction. to

close blade 14, the plate 70 is likewise moved in a clockwise direction around its pivot 71.

'In so doing the upper edge of plateA 70 abuts against a projection 73 on arm 39, and rotates thisarm in opposit-ion to the -pull of spring 40. f At the time blade 14 reaches its final position, the arm 39 is returned by this control to a position slightly higher than noV ,in a -counterclockwise direction, far enough so as to position the projection 47 under the projection 46. 'In this way there is a positivelocking movement of vlever V50, entirely independent of the condition of wires 58 and 59. As soon as the handlel is ro? `vtated in a clockwise direction to move' blade into closing position, the plate 70 is cor- 'moved in a countrclockwise responding] direction. This permits spring 40 to act and pull projection 46 against projection 47, and

thus the latching of blade 14 is completed.

The control plate finally takes the position shown in Fig. 1, upon completion of the movement of blade `15. The controller is thus in posi-tion to respond to an overload or to a short circuit.v lIn order that the resetting operation be properly performed, it is'essential that the various elements of the control plate 70 be so proportioned that the various movements caused by it take' place inA the order setl forth. This however is a comparatively eas matter to accomplish. 'Ihe member 48 is or ease of operation made separate from lever 50 so as to ro- ]'ection 46 to pass beyond projection 47 w ile the mechanism is bein reset. Itis for this purpose also that the e ges of projections 46 port the top base 11. The other terminal of'` the load 76 is connected to a similar conducting strip 78. Between conducting strip, 77 and the spring plates 23 of blade 14 extend the wire 59 as well as a shunt 79 of conductv ing material.. Ina somewhat 4similar man-4 f ner the wire 58 extends between strip 78 and the clips 28, while another shunt 80 parallels this wire. These two shunts are for convenience Adisposed between the bases 11 and 17, and are therefore hidden from view Y in Fi 1 and 2. However, it is thought that the iagram of Fi 4 is suiiciently clear in this regard. It 1s to be understood also that both shunts` are of substantially identical length and cross section, as is true of the active portions, of wires 58 and 59. Furthermore in order to calibrate the apparatus it is possible to multiply the shunts, so that instead of a single conductor forming a.

' shunt between parts 77 .and 23 for example,v

a plurality of substantially identical conductors may. be` used. Each conductor is preferably so proportioned that it has e -larger resistance than the lcorresponding wire 58 or 59. This may be accomplishe by making the shunts out of the proper conducting material, or by making them of the same material but longer than the wires 58 and 59.- |When this is done, the heating of the shuntsis much less than of the wires and there is no danger tha-t there will be any The complete circuit for the apparatus and the load, when the contacts are closed, may now be traced. Entering at lead 19, the circuit continues to bar 16, clips 12 and 12', blade 14 and clips 23, where it divides, part of the current going through wire 59 to member 7 7,`and the rest through shunt 79 to `member 77; from this member the current lincrease inthe temperature of the wiresdue to the proximity of the shunts. 75

. The embodiments of the various mechanicalv expedients disclosed may, and very likely would, be varied to suit varying conditions of operation.` The features which I con- Sider essential for the practice of my inven- -tion are set forth in the claims appended to the specification.

At this point itis advisable to review in acondensed manner the operation of the de-l vlce as embodied in the-apparatus illustrat ed. .Assume that the contacts are closedas 1n Fig. 1.' Upon the occurrence of a short roo circuitor an overload, the wires 58 and 59 expand, and permit spring 55 to rotate lever 50 so as to free the projection 46 of arm 39. Thereupon spring 40 rotates this arm, and

frees projection 42 from the path of blade 14. The spring 24 is now permittedto act, and blade 14 opens. Inso doing, the pin 36 rotates the lever32 `to the position shown in arm. The projection 42 is returned and re" tained in the position shown in Fig. 1. The A. handle 31 is now pulled-up until blade 15 enters clips 13, and the circuit is a ain completed. Due to the plurality o triggers placed one after another between the movement of lever 50 and the .unlatching of blade 14, it Vis possible to ensure against failure of operation, since in this way a comparatively light force acting on lever 50 is sucient to unlatch the blade.

ammo

I claim: Y

1. In a circuit controller, a pair of switch blades, a pair of contacts cooperating with said blades, means urging said blades to open position, means for holding one of `said b ades in closed position, and means active only while that blade is in closed position for holding the other blade in closed posin tion.

2. In a circuit controller, a pair of switch. blades, a pair of contacts cooperating with` said blades, a handle for moving one of said blades, means whereby movement of this handle to move the blade with which it is associated toward open position, serves to move the other blade to closed position, a catch for holding the blade with which the handle is associated, in closed position, and

means whereby the other bladereleases said catch when that .other blade is in'open position. s

3. In a circuit controller, a conductor adapted to expand under the inluence of heat generated init by the assage of an electric current, means where y the expansion operates the controller, a member to which one'end 'of the conductor isv attached, and a metallic bar carrying the member at one end and fastened at the other, whereby variations in the air temperature result in varying the osition of the member.

4. In com ination, a pair of conductors adapted to expand under the inuence of heat generated in them by the passage of an electr1c current, a lever p1voted intermediate its ends, and fastened on opposite sides of the pivot oint tothe conductors, al metallic bar to wh1ch the lever is pivoted, and means for .holding one end of the bar stationary which is remote from the lever comprising an adjustable abutment against wh1ch the bar rests.

5: In a circuit controller, a pair of conductors adapted to'expand under the influence of heat generated in them by the passage of an electric current, a metallic bar, an adjustable abutment for one end of the bar, a lever pivoted near the other end of the bar, between the extremities of the lever, the conductors being fastened to opposite sides of the lever, and means whereby the expansion of the conductors causes operai tion of the controller.

6. In a circuit controller, a pair of relatively movable contacts for controlling one side of a circuit, another pair of relatively movable contacts for controlling the other side, means tending to urge said sets of contacts to open position, latches for holding them. in closed position, means for un latching one of said sets of contacts in response to load conditions in a circuit, and means whereby the other set is unlatched in response to the unlatching of the first set.

7. circuit controller having two pairs of contacts for controlling both sides of the circuit, means tending to operate said pairs of contacts to open the circuit, latches for the contacts to hold them closed, and a conductor adapted by its expansion due to the flow of current therethrough to release one of said latches, characterized by the fact that the release of the other latch is dependent upon the opening of the contacts controlled by the first latc 8. In a circuit controller, a pair of contacts, means urging said contacts apart, a

latch for holding the contacts closed, and

means for closing the contacts from the open position com rising means for moving the contacts to et er, and a movable member operated by t e operation of said latter means to move the latch to hold the contacts closed.

9. In a circuit controller, a pair of con-- tacts, means urgingsaid contacts apart, a latch for holding the contacts closed, means urging the latch to open osition, a member responsive to circuit con itions for permitting` said latter means to act, and means for closing the contacts from open position and maintaining them closed comprisin means for movin the contacts together, an a movable mem r operated Iby the operation of said latter means to move the` latch to closed position and the member which is responsive to circuit conditions so as to retain the latch. y

10. In a circuit controller, a pair of switch blades, contacts coo rating with said blades, means for movmg one of said blades so that itA urges the other to closed position, means tending to o en the blades, a latch for holdin that bla e closed which is moved by the ot er, means tending to open the latch, a member responsive to circuit conditions for preventing said latch from o ening, and a pivoted control plate rotate by the movement of the blade to closed posltion for setting the latch and moving the circuit condition responsive member to its holding position.

In testimony whereof, I have hereunto set m hand.

y OTTO P. CRAMEB. 

